1. Field of the Invention
This invention relates to a radio-controlled model, more particularly to a ducted fan assembly for use on a radio-controlled model airplane.
2. Description of the Related Art
As illustrated in FIG. 1, a conventional ducted fan assembly 10 for a hobby radio controlled (R/C) model airplane includes a housing 11, an electric motor 12 disposed inside the housing 11, and a high-speed propeller unit 13 mounted on one end of the electric motor 12. The housing 11 has a seat member 112 that allows mounting of the electric motor 12 thereinside. A power cord 121 passes through the seat member 112 and the housing 11 for connection to a power source (not shown). The motor 12 has a rotating shaft 122 that drives the propeller unit 13.
The conventional ducted fan assembly 10 has several disadvantages as follows:                1. Ineffective heat dissipation. Since the motor 12 is entirely embedded in the seat member 112 and isolated from the surrounding airflow, the motor 12 is unable to experience quick and efficient heat dissipation.        2. Difficult installation. Since the motor 12 is embedded in the seat member 112, in order to connect the power cord 121 of the motor 12 to the power source, the power cord 121 must first pass through the housing 11 and the seat member 112. This makes installation of the conventional ducted fan assembly 10 in the R/C model airplane a cumbersome task.        3. Noise and reduced efficiency. A hole must be drilled in the housing 11 in order for the power cord 121 of the motor 12 to connect to the power source. This may result in air leaks if sealing is not conducted properly. Hence, when the propeller unit 13 induces an airflow through the housing 11, if an airtight seal is not in place, the airflow can escape through the hole to thereby generate unwanted noise and reduce the efficiency of the conventional ducted fan assembly 10.        